Dedicated core networks (DCN) selection

ABSTRACT

The invention provides for a method of selecting a Dedicated Core Network (DCN) based on assisting indication by mobile terminals, and including the step of configuring the RAN Nodes of the mobile network with the DCN Types of the serving EPC Nodes so that the RAN Nodes can map the DCN selection assisting information from the connecting mobile terminals with the right dedicated EPC Node. This allows for the RAN Node to connect the mobile terminals with EPC Node of the mobile terminal&#39;s dedication at initial attach and then keep the mobile terminals on the same DCN. Thus, a re-routing of mobile terminals NAS message from one EPC Node to another EPC node is avoided. The invention also allows for a flexible and dynamic change of the EPC Nodes dedication based on operator&#39;s configuration and policy. Additionally, the invention allows for DCN access restriction control by broadcasting of the supported DCN Types by the RAN Node.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a National Stage Entry of International ApplicationNo. PCT/JP2016/004477, filed Oct. 5, 2016, which claims the benefit ofpriority from European Application No. 15189240.3, filed Oct. 9, 2015.The entire contents of the above-referenced applications are expresslyincorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to a dedicated core networks (DCN) selection.

BACKGROUND ART

3GPP networks are beginning to support devices and customers with verydifferent characteristics, such as device for Machine Type Communication(MTC), Internet of Things (IoT), data usage, etc. These classes ofdevices and customers may have different requirements from the corenetwork in terms of optional feature support, traffic characteristicsupport, availability, congestion management, ratio of signalling touser plane traffic, etc. As we move forward, the classes ofdevices/customers will continue to increase.

TABLE 1 Abbreviations DCN Dedicated Core Network EM Element Manager eNBevolved Node B E-UTRAN Evolved Universal Terrestrial Radio AccessNetwork GPRS General Packet Radio Service HSS Home Subscriber Server IoTInternet of Things MME Mobility Management Entity MMEG1 MME GlobalIdentity MTC Machine Type Communication NAS Non Access Stratum NMNetwork Manager NNSF NAS Node Selection Function NRI Network ResourceIdentifier OAM Operations, Administration and Management PCRF Policy andCharging Rules Function PGW Packet Data Network Gateway RAU Routing AreaUpdate RNC Radio Network Controller SDT Small Data Transmission SGSNServing GPRS Support Node SGW Serving Gateway TAU Tracking Area UpdateUE User Equipment UTRAN UMTS Terrestrial Radio Access Network

One cost effective mechanism for operators to support these differentclasses of devices and customers is to create separate dedicated corenetworks consisting of specialized core network elements that aredesigned and deployed to meet the requirements of these differentdevices and customers. It is cost-effective as the network availabilityor redundancy requirements may be easier met with different hardwareand/or software than the existing core network. Also, creating separatecore networks enables independent scaling or specific featureprovisioning for specific user or traffic types and isolating specificusers and traffic from each other.

3GPP started work on standardisation of Dedicated Core Networks inRel-13 (TR23.707) and agreed a network solution with no UE impact, seeTS23.401, s4.3.2.5. This Rel-13 feature enables an operator to deploymultiple DCNs (Dedicated Core Networks) Within a PLMN with each DCNconsisting of one or multiple core network nodes. Each DCN may bededicated to serve specific type(s) of subscriber or devices. This is anoptional feature and enables DCNs to be deployed for one or multipleRATs (GERAN, UTRAN and E-UTRAN).

When DCNs are supported (deployed), at initial access to the network, ifsufficient information is not available for RAN to select a specificDCN, the RAN may selects a core network node from the default CN. Aredirection to a DCN may then be required.

To redirect a mobile terminal from a default CN to a dedicated CN, theredirection procedure via RAN, described in clause 5.19.1 of TS23.401,is used to forward the NAS message from the UE to the target DCN. Allselection functions are aware of DCN(s), including the network nodeselection function (NNSF) of RAN nodes, for selecting and maintainingthe appropriate DCN for the UEs

SUMMARY OF INVENTION Technical Problem

The Rel-13 DCN selection solution was not allowed to impact the UE sothat it supports Rel-13 and earlier release mobile terminals. For thisreason it has a main disadvantage— at initial access to the network asufficient information is not available for RAN so that it can selectthe right dedicated DCN at the very beginning instead of selecting firsta default EPC Node (e.g. MME or SGSN) and then rerouting the mobileterminal to the right DCN. This creates extra signalling and delay.

In Rel-14 the 3GPP has started a Work Item (S2-152661) on enhanced DCNwith the following objectives:

-   -   Improve DCN selection mechanism by providing assistance        information from the UE. This assistance information complements        the Rel-13 DECOR mechanism. This can reduce the signalling        required to register to and maintain a DCN. It can also improve        isolation between dedicated core networks since there is no need        for redirecting between different DCNs. The updated selection        mechanism impacts the UE and RAN but the provisioning of the        assistance information may impact the core network. It is        advantageous if the solution works when the UE changes PLMNs.

It is however unclear how the RAN takes a decision for routing of theUE's message towards the core network.

With this new ongoing work the problem which this invention is trying tosolve is how to enable the RAN Node (e.g. eNB or RNC or CIoT RAN) totake a decision about the routing of the UE's message (e.g. NAS message)towards the correct (dedicated) core network.

Solution to Problem

In one aspect, the invention provides a radio access network nodecomprising: a receiver configured to receive from a core network nodeconnected to the radio access network node a message for configuringwith a dedicated core network supported by the core network node.

In one aspect, the invention provides a communication method for a radioaccess network node, comprising: receiving from a core network nodeconnected to the radio access network node a message for configuringwith a dedicated core network supported by the core network node.

In one aspect, the invention provides a mobile terminal comprising: atransmitter configured to transmit to a radio access network nodeinformation for indicating a dedicated core network at registration to anew location in a network included in the radio access network node.

In one aspect, the invention provides a communication method for amobile terminal comprising: transmitting to a radio access network nodeinformation for indicating a dedicated core network at registration to anew location in a network included in the radio access network node.

In one aspect, the invention provides a communication method for acommunication system, comprising: receiving, by a radio access network,from a core network node connected to the radio access network node amessage for configuring with a dedicated core network supported by thecore network node; transmitting from a mobile terminal to the radioaccess network node information for indicating a dedicated core networkat registration to a new location in a network included in the radioaccess network node; and selecting, by the radio access network node,the core network node based on the information for indicating thededicated core network received from the mobile terminal.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a RAN Node configuration with the dedication type ofthe CN node.

FIG. 2 illustrates a list of supported DCN Types of the RAN Node withinthe MME Configuration Update message.

FIG. 3 illustrates the DCN Type list configuration in the RAN Node.

FIG. 4 illustrates one of the System Information messages/blocks a listof all supported DCN Types in that RAN Node.

FIG. 5 illustrates the DCN Type which can also be passed further, fromRAN Node to the EPC Node within Initial UE Message or any other NASmessage.

FIG. 6 illustrates that the RAN may forward the UE's UE Usage Typeindication to the EPC Node within the S1-AP's Initial UE message.

FIG. 7 illustrates one practical exemplary of how to select the rightDCN.

FIG. 8 illustrates a scenario where the network does not support a DCNfrom the same type that the UE has indicated to RAN Node during the RRCconnection establishment.

FIG. 9 illustrates an exemplary architecture for the configuration ofnetwork nodes.

DESCRIPTION OF EMBODIMENTS

Solution Alternative 1.

The following solution in FIG. 1 is proposed to assist a Dedicated CoreNetwork (DCN) selection by the mobile terminals based on the DedicatedCore Network type provided by the mobile terminals (DCN type, CIoT type,UE Usage Type or any other type of identity for a dedicated type of corenetwork).

Step 1) RAN Node Configuration with the Dedication Type of the CNNode—Provide

RAN Nodes (eNB or RNC or CIoT RAN Node) with the DCN (Dedicated CoreNetwork) Type(s) of the EPC Nodes (MME or SGSN or CIoT EPC Node) thatRAN Node is connected to. The DCN Type of the EPC Node (MME/SGSN/CIoTEPC), i.e. the type of users, services or devices the EPC Node isspecialised or dedicated for, could be identified with the same typesthat already were agreed by the 3GPP for identification of the UEsubscription type in the HSS, i.e. ‘UE Usage Type’ (see TS23.401) oralternatively with MMEGI or NUL-NRI/SGSN Group Id that in 3GPP Rel-13were agreed to identify a dedicated MME Pools or SGSN Pools. The MME'sDCN Type could also be identified with so called ‘MME Usage Type’ (whichwould be the UE Usage Type per MME) that would allow compatibility withthe already existing ‘UE Usage Type’ . . . . The DCN Types of the EPCNodes (e.g. MMEs) may be configured via OAM or locally based onoperator's configuration and policy.

The EPC Node indicates to the connected RAN Nodes the types of the usersor mobile terminals (UEs) it is specialised to serve (DCN Type list) sothat the RAN Node can select the right dedicated network when a UEconnects to the RAN Node.

As mentioned above, one alternative would be when the UEs and EPC Nodesuse the “UE Usage Type” as indication for DCN Type, but otherindications can be used, as well. Another alternative is the MME'sindication to the RAN node for DCN Type is different from the UE'sindication to the RAN node. In this case, the RAN node needs to haveinternal mapping mechanism to map the DCN Type from the UE to thecorrect dedicated EPC Node. One example of the latter alternative iswhere the UE indicates in the DCN Type “delay tolerant”, for examplewhereas the EPC Node (e.g. MME) indicates “M2M” DCN Type. The mappingbetween the UE's indication and the EPC Node's indication in the RANnode can be done via configuration over the OAM system, for example orvia an internal logic in the RAN node.

In addition, DCN may have an associated DCN Profile and the DCN Profilecan be also sent to RAN Node together with DCN Type. The DCN Profile maycontain parameters that defines DCN characteristic that are specializedto serve predefined service(s). The DCN Type can be considered as anetwork slicing mechanism, thus an associated DCN Profile may define thenetwork slice characteristics

The DCN Type list (e.g. ‘UE Usage Type’ list or MMEGI/SGSN Group IDlist) can be provided by the EPC Node to the RAN Node with the followingmessages:

Step 1A) MME Configuration Update Message.

During the MME configuration the MMEs provide a list of supported DCNTypes to the RAN Node within the MME Configuration Update message(TS36.413, s8.7.5), see FIG. 2. This allows the RAN Nodes to beconfigured with information about the UE's DCN Type (e.g. ‘UE UsageType’ or designated MMEGI) served by the MMEs that the RAN Node isconnected to so that the RAN Node uses this information to select theright MME when the UE connects for service. If parameters other than ‘UEUsage Type’ are used for DCN Type, a mapping between the DCN Typeindication and the UE subscription type may be required. This mappingneeds to be configured in the RAN node.

Step 1B) S1 Setup Response Message

(TS36.413, s9.1.8.5). During the S1 Setup procedure the EPC Node (e.g.MME) may provide or update the DCN Type list (e.g. ‘UE Usage Type’ listor MMEGI list) configuration in the RAN Node, see FIG. 3. This wouldallow not just for the DCN Type configuration in the RAN Node but for adynamic configuration update of the DCN Type list in the RAN Node basedon operator's policy or operator's configuration.

Step 1C)—

any other signalling exchange between the EPC Node (MME or SGSN or CIoTEPC Node or any other name for the dedicated network node) could be usedto configure the RAN Node with the specialization type of the dedicatedEPC Nodes.

In yet another aspect applicable to any of the options 1A), 1B) or 1C)from above, it is possible that the RAN node may indicate to the EPCnode whether the RAN node supports the feature of EPC node (e.g. MME)selection function based the DCN Type list from the EPC node. This kindof capability indication from the RAN node may be used by the EPC Nodeto make a decision whether DCN Type list needs to be set in thesignalling from the EPC node to the RAN node. Especially in cases wherethe DCN type list announced from the EPC node may change frequently andthe EPC nodes needs to update the RAN nodes in a frequent manner, sothat updating only the supporting RAN nodes instead of all RAN nodes maybe beneficial.

Once the RAN Node obtains the DCN Types from the associated EPC Nodes(e.g. MMEs) as shown in FIG. 2 and FIG. 3, the RAN Node may utilize DCNType and associated DCN Profile to perform RAN slicing per service(s).If RAN Node receives the same DCN Type from multiple EPC Nodes, then RANNode shall consider all DCN Profiles associated to the same DCN Typefrom different EPC Nodes as one aggregated network slice spanned tomultiple EPC Nodes.

In one aspect, when the RAN Node obtains the DCN Types from theassociated EPC Nodes (e.g. MMEs) as shown in FIG. 2 and FIG. 3, the RANNode may broadcast in one of the System Information messages/blocks(over BCCH channel, for example) a list of all supported DCN Types (e.g.DCN Type list) in that RAN Node, see FIG. 4. This would allow the UEs toobtain an information about the supported DCN Types by the RAN Node andthe UEs would attempt to connect only, if the DCN Type they aresubscribed to, is supported. This would allow for an efficient DCNAccess control by restricting the access to a specific DCN(s) when it isnot supported in that RAN Node or temporary not available (overloaded orfailure) or any other reason based on operators' policy andconfiguration. Thus, the extra signalling from access failures could beavoided and UE battery power saved.

If the RAN Node (based on operator's policy or configuration) isconfigured to select a default MME when an MME(s) of specific dedicationare not available, then the RAN Node does not broadcast DCN Types list(i.e. no DCN access restriction).

In another aspect this can be also done on a per UE basis instead of ageneral configuration for all UEs at the RAN node, i.e. the EPC Node(e.g. MME) will provide the DCN Type list when the UE sends the initialUE message. The EPC node then can map for inbound roaming users thelocal (VPLMN) DCN Types to the ones supported in the HPLMN of said UE.For example, if the meaning of the UE Type is different in the differentnetworks and the UE Usage Type sent by the UE is considered fixed forthe time being, then at time of the initial attach to the VPLMN, theVPLMN EPC Node would receive the subscriber profile from the HPLMN EPCnode including the DCN Type. The VPLMN EPC node would then chose theappropriate DCN Type for this UE and send it in the reply message e.g.in S1AP, to the RAN node. This means the same MME could send differentsupport values to the same RAN node for different inbound roamers. Themeaning of the DCN Type is then on a per UE granularity.

After receiving the ‘DCN Type list’ indication from the EPC node, theRAN node stores the ‘DCN Type list’ together with the EPC node ID (e.g.MME ID). The RAN node is able to generate a mapping table of allreceived DCN Types and the corresponding MME IDs. This mapping table canbe used by the RAN node to select a direct match or the most appropriateserving node, to which to route the UE's NAS message, as there may bemultiple serving nodes serving the same DCN type indicated from the UE.

Step 2). DCN Type Indication by Mobile Terminals (e.g. UE, MS, MTCDevice, CIoT Device or any Other Type of 3GPP Compatible Terminal).

The UE can indicate its DCN Type (‘UE Usage Type’ subscription or MMEGIidentity for the required dedicated resource or any other type ofsubscription indication or user characteristics or targeted serviceprovider or targeted application which could have been preconfigured inthe UE, SIM or UICC) during the RRC connection establishment procedure.The RAN node can select the right type of DCN (EPC Node like MME or SGSNor CIoT EPC Node) from the very beginning, i.e. avoiding any possibilityfor re-routing from a default EPC Node to a dedicated EPC Node. The DCNType can be indicated within the RRC Connection Setup Complete message,see FIG. 5 or any other message within the connection establishmentprocedure or via NAS message.

The RAN Node has been configured with a list of DCN Types supported byeach MME it is connected to, see step 1). During RRC Connectionestablishment the UE indicates its DCN Type (‘UE Usage Type’ or theMMEGI of a dedicated resource) which is used by the RAN Node to selectthe right MME to connect to. The UE can optionally indicate its DCN typeonly during RRC connection establishment for Mobile Originated (MO)services. If the RAN Node has been configured by the EPC Nodes with DCNType different from the DCN Type received from the UE (e.g. in roamingscenarios where one or both, home and visited PLMNs deploy PLMN specificvalues for DCN Type or in non-homogeneous coverage of DCNs), a mappingbetween the DCN Type from the UE and the DCN Types from the EPC Nodes,based on operator's policy or configuration is required.

Other RRC Connection Establishment messages (e.g. RRC ConnectionRequest) can also be used for indication the UE's DCN Type from themobile terminal to the RAN Node where the behavior of the RAN Node wouldbe similar or same to the case when the DCN Type indication from the UEis received within the RRC Connection Setup Complete message.

If the UE does not indicate any DCN Type to the RAN Node, then the RANNode behavior would be as specified in TS23.401 for Rel-13—RAN Nodewould forward the UE to a default MME if there is no other availableinformation about the UE's or user's DCN dedication.

Optionally, if RAN Node is not configured with the DCN Types (e.g. ‘UEUsage Type’, or MMEGI or any other way of identification for a dedicatedEPC resource) or the RAN Node cannot decode the DCN Type indicated bythe UE, the DCN Type can also be passed further, from RAN Node to theEPC Node (e.g. MME or SGSN or CIoT EPC Node) within Initial UE Messageor any other NAS message, as shown in FIG. 5. So the EPC Node cananalyse the DCN Type from the UE and map it to the right dedicatednetwork, based on operator's policy or local configuration.

In another aspect (FIG. 6) the UE can indicate its DCN Type (e.g.subscribed UE Usage Type in a container within the above mentioned RRCmessages (e.g. RRC Connection Setup Complete or RRC Connection Requestor any other AS or NAS message), especially when DCN Type is anon-standardised one (e.g. the DCN Type is the UE Usage Type which has aPLMN specific value, see FIG. 6). A ‘UE Usage Type’ flag parameter inthe above messages would indicate whether the ‘UE Usage Type’ in the UEUsage container is standardised or it is PLMN specific (e.g. a simpleflag to indicate via I/O or True/False or Standardised/PLMN specific thetype of the ‘UE Usage Type’ element in the UE Usage Type container.

If the ‘UE Usage Type’ is globally standardised, the ‘UE Usage Type’container from the UE would be the standardised ‘UE Usage Type valueitself.’

If the ‘UE Usage Type’ is PLMN specific (non-standardised), the UE UsageType container would contain:

-   -   either the Home PLMN specific values for the ‘UE Usage Type’ in        the UE Usage Type container which would be analysed by the RAN        Node or the EPC node based on the operators roaming mapping and        configuration and policies;    -   or the Home PLMN provide the UE (over the air or via        terminal/SIM/UICC configuration) with the ‘UE Usage Type’ values        for the roaming partners so that the UE can use the visited        PLMN's ‘UE Usage Type’ values in the UE Usage Type container        when roaming.

FIG. 6 further shows that the RAN may forward the UE's UE Usage Typeindication to the EPC Node within the S1-AP's Initial UE message. The UEUsage Type indication from the UE can be used by the EPC Node to verify(with the HSS for example) the validity of the UE subscription. In sucha case there is no need for the UE to indicate the “DCN Type” in the NASsignalling. The RAN node may need to have internal processing unit inorder to decide whether to forward the UE's indication over the ASsignalling to the S1-AP signalling over the S1-MME interface. In oneexample the eNB may always forward the UE's AS indication on the S1-MMEinterface to the EPC Node. In another example the eNB may forward theUE's AS indication depending on the indication value. In yet anotherexample the RAN node can forward the UE's AS indication dependingwhether the value of the UE's AS indication is known to the RAN node (orwhether the RAN node is configured with the value) to map to any of theavailable DCNs.

The diagram in FIG. 7 demonstrate one practical example of how to selectthe right DCN based on the above steps.

1-2) EPC Nodes (e.g. MMEs) provide a list of supported DCN Type(s) tothe RAN Node within the MME Configuration Message (TS36.413, s8.7.5) orany other message on the MME/eNB

interface. The DCN Type could be represented with the already 3GPPdefined ‘UE Usage Type’ (i.e. the DCN Type values aligned with the ‘UEUsage Type subscription values’ in TS23.401 for Rel-13) or via MMEGIthat is designated for a dedicated MME Pool or any other way ofdedicated resource identification. This allows the RAN Nodes to beconfigured with information about the DCN Types served by the MMEs thatthe RAN Node is connected to so that the RAN Node uses this informationto select the right MME when the UE connects for service. In the aboveexample one of the MMEs is of ‘default’ type (a conventional,non-dedicated MME) and another one is of ‘mtc’ (Machine TypeCommunication) and ‘ciot’ (Cellular Internet of Things) types (e.g.‘mtc’ and ‘ciot’ UE Usage Type values). It is also possible that defaultMMEs do not indicate any DCN Type list (e.g. it is not present orempty), which would mean that all DCN Types are supported.

This way the RAN Node is configured with the list of DCN Types supportedby each MME the RAN Node is connected to.

3A) When a UE triggers RRC Connection establishment for a MO service theUE indicates (in the RRC Connection Setup Complete message, for example)its DCN subscription via DCN Type parameter=‘mtc’, for example.

4A) Based on the DCN Type=‘mtc’ indication from the UE, the RAN Nodeselects a ‘mtc’ dedicated EPC Node (from the same type as the DCN Typereceived from the UE). The RAN Node forwards the NAS message from the UEto the MME with ‘mtc’ type dedication along with the DCN Type indicationparameter from the UE for subscription verification with the HSS.3B) When UE triggers RRC Connection establishment for a MO service theUE indicates (in the RRC Connection Setup Complete message, for example)its DCN subscription via DCN Type parameter=‘ciot’, for example.4B) Based on the DCN Type=‘ciot’ indication from the UE, the RAN Nodeselects a ‘ciot’ dedicated EPC Node (from the same type as the DCN Typereceived from the UE). The RAN Node forwards the NAS message from the UEto the MME with ‘ciot’ type dedication along with the DCN Typeindication parameter from the UE for subscription verification with theHSS.3C) If a UE triggers RRC Connection establishment for a MO service theUE indicates (in the RRC Connection Setup Complete message, for example)its DCN subscription via DCN Type parameter=‘sdt’, for example4C) Based on the DCN Type=‘sdt’ (Small Data Transmission) indicationfrom the UE, the RAN Node attempts to select a ‘sdt’ dedicated EPC Node(from the same type as the DCN Type received from the UE). As adedicated MME from ‘sdt’ type dedication is not available, the RAN Node,based on operators configuration or policy, either

-   -   forwards the NAS message from the UE to the MME with ‘default’        type dedication along with the DCN Type indication parameter        from the UE. The default MME, depending on the operator's        configuration can serve the UE or reject the NAS message from        the UE with back-off timers included in the reject or        alternatively forward the NAS message from the UE to an MME from        different dedication if required by operator's policy or        configuration; or    -   the RAN Node forwards the NAS message from the UE to another        dedicated resource (MME) again, based on the local configuration        or operator policies.

The diagram in FIG. 8 illustrates a scenario where the network does notsupport a DCN from the same type that the UE has indicated to RAN Nodeduring the RRC connection establishment (e.g. in the RRC ConnectionSetup Complete message or RRC Connection Request message or any otherRRC signalling). i.e. RAN Node is not associated with a dedicatednetwork from the ‘DCN Type’ indicated by the UE. In this case, onepossible behaviour (other than forwarding the UE to a default EPC Node)is that the RAN Node rejects the UE by releasing the already created RRCconnection via RRC Connection Release message returned to the UE alongwith a new release cause, e.g.:

-   -   ‘DCN not supported’ (or any other name with similar meaning)—a        DCN of the DCN type indication by the UE is not supported by        this RAN Node.    -   ‘DCN not available’ (or any other name with similar meaning)—the        DCN is temporary not available because of failure or any other        reason.

On receiving the RRC Connection Release message with the release cause:

-   -   ‘DCN not supported—the UE shall not initiate another attempt for        RRC connection to the same DCN while the UE is in the same        TA/LA;    -   ‘DCN not available’—the UE shall not initiate another attempt        for RRC Connection establishment while the UE is in the same        Cell. If an ‘extended wait timer’ is present in the RRC        Connection Release message, the UE can try another RRC        connection establishment in the same cell when the ‘extended        wait timer’ expires.        Solution Alternative 2:

Another possible solution of the described problem is to configure theRAN nodes (e.g. eNBs) in a proper way to forward the UE's message to thecorrect DCN. This configuration can be e.g. done over the OAM system.Alternative 2 is a more static way of configuration via the OAM. Thus,this solution is applicable to networks whose DCN configuration does notchange frequently.

FIG. 9 shows an exemplary architecture how to configure the RAN node andserving network node, more particular a base station, eNB and MME, usingthe Operations, Administration and Management (OAM) system. Usually theRAN node (e.g. eNB), and the network node (e.g. MME) implements anElement Manager (EM). The EM is connected to the network manager (NM)which is part of the OAM system operated by the network operator.

In the particular scenario of this invention, the network operator canuse the OAM system to configure the RAN nodes (eNBs) with the particularmapping of the UE's DCN Type indication and the serving node configuredto serve the particular DCN Indication. The OAM system can be also usedto configure the serving network node with the corresponding DCN types.The eNB is able to route the UE's NAS message to the correct servingnetwork node based on the ‘DCN type’ indication from the UE. With otherwords the configuration of the RAN node to map the ‘DCN type’ indicationfrom the UE to the available DCN types of the serving node is similar asthe configuration of the eNB from Alternative 1 above.

The configuration can be done in a kind of table containing e.g.

-   -   UE “DCN type” indication maps to MMEGI(s) or SGSN group ID.    -   UE “DCN type” indication maps to MME ID or SGSN ID.

Having such a configuration, the eNB can take a decision how to select aparticular serving node (MME) to which the UE's NAS message isforwarded.

Although the proposed solutions in this invention mostly use 4Gterminology in the description and examples (UE, MME, eNB and etc.) thesolutions are equally applicable to 3G/2G technology (including terminalindicated as MS, and network nodes SGSN, MSC, RNC, Base Station andetc.) as to any old or new 3GPP compatible technology, IoT networks andterminals and more.

SUMMARY OF THE ASPECTS OF THE DISCLOSURE

-   -   1. MME Configuration Update (DCN Type list)—New parameter DCN        Type list in the MME Configuration Update message that contains        the list of the DCN Types (e.g. UE Usage Types or MMEGI or any        other way of identification for a dedicated EPC resource)        supported by the connected MME. This allows the MMEs (connected        to a specific RAN Node) to configure that RAN Node with the DCN        Types they are dedicated to serve.    -   2. RRC Connection Setup Complete (DCN Type)—New parameter DCN        Type in RRC Connection Setup Complete message (or any other AS        or NAS message from the UE) so that the UE can indicate to the        RAN Node its subscription for dedicated network (e.g. via ‘UE        Usage Type’ or MMEGI or any other way to identify the UE's        dedicated network subscription).

In an alternative implementation two new parameters could be added tothe RRC Connection Setup message—RRC Connection Setup Complete (UE UsageType flag, UE Usage Type container) to cover roaming between PLMNs whereone or both of the PLMNs uses PLMN specific values for the UE UsageType. In this case the UE Usage flag would indicate whether the UE UsageType value in the UE Usage Type container from the UE is a standardizedone or PLMN specific one.

-   -   3. Dedicated EPC Node selection by RAN Node (e.g. eNB)—Based on        the configuration by the MME with the DCN Type list and the DCN        Type indication from the UE, the RAN Node selects the right        dedicated EPC Node to service the UE.    -   4. Initial UE Message (DCN Type)—New parameter in the Initial UE        Message so that the dedicated MME can verify the UE subscription        for DCN or alternatively, when the dedicated core network        selection would be made by the EPC Node (e.g. when the dedicated        resource selection information in the RAN Node is still        insufficient).    -   5. RRC Connection Release (release cause)—RAN Node can reject        the UE when a dedicated network of the DCN Type indicated by the        UE is not available or not supported. The new values for the        release cause—DCN not supported and DCN not available.    -   6. DCN Type list broadcast in the System Information—RAN Node        may broadcast the list of DCNs supported by it—DCN access        control by the RAN Node. If a default MME is present in the MME        Loop (service area), the RAN Node may not broadcast any DCN Type        list as it is possible that the default MME is configured (based        on the operator's policy) to serve the UEs for which there is no        DCN support.

Exemplary Advantages of the Disclosure

-   -   1. UE NAS Message Reroute is avoided. As the UE provides its        subscription for dedicated network via the DCN parameter and        also the RAN Node is configured with the MME's DCN Types, the        RAN Node can select the right dedicated resource without having        to forward the NAS message from the UE to a default MME    -   2. Improved Load Balancing by the RAN Node. As the RAN Node is        provided with the DCN Types supported by the connected MMEs, the        RAN Node can select a dedicated MME by applying the existing        load balancing principles only for MMEs of the same DCN Type.

This application is based upon and claims the benefit of priority fromEP Patent Application No. 15189240.3, filed on Oct. 9, 2015, thedisclosure of which is incorporated herein in its entirety by reference.

The invention claimed is:
 1. A radio access network node comprising: afirst receiver configured to receive, from a core network node coupledto the radio access network node, a message for configuring with atleast one network slice supported by the core network node, wherein themessage includes first information for the at least one network slice; atransmitter configured to transmit second information indicatingavailability of the at least one network slice; a second receiverconfigured to receive, from a mobile terminal which receives the secondinformation, a Radio Resource Control (RRC) setup complete messageincluding third information indicating a first network slice from amongthe at least one network slice; a memory storing instructions; and atleast one processor configured to process the instructions to select acore network node specific for the first network slice based on thethird information indicating the first network slice.
 2. The radioaccess network node according to claim 1, wherein the message isreceived via Operation And Maintenance functions.
 3. A communicationmethod in a radio access network node, comprising: receiving, from acore network node coupled to the radio access network node, a messagefor configuring with at least one network slice supported by the corenetwork node, wherein the message includes first information for the atleast one network slice; transmitting second information indicatingavailability of the at least one network slice; receiving, from a mobileterminal which receives the second information, a Radio Resource Control(RRC) setup complete message including third information indicating afirst network slice from among the at least one network slice; andselecting a core network node specific for the first network slice basedon the third information indicating the first network slice.
 4. Thecommunication method according to claim 3, wherein the message isreceived via Operation And Maintenance functions.
 5. A mobile terminalcomprising: a receiver configured to receive, from a radio accessnetwork node, second information indicating availability of at least onenetwork slice; and a transmitter configured to transmit to the radioaccess network node, a Radio Resource Control (RRC) setup completemessage including third information indicating a first network slicefrom among the at least one network slice, and wherein the mobileterminal is served by a first core network node which is selected by theradio access network node based on the third information indicating thefirst network slice, the at least one network slice being indicated by amessage including first information for the at least one network slice,received from a second core network node which supports the at least onenetwork slice.
 6. A communication method for a mobile terminalcomprising: receiving, from a radio access network node, secondinformation indicating availability of at least one network slice; andtransmitting to the radio access network node, a Radio Resource Control(RRC) setup complete message including third information indicating afirst network slice from among the at least one network slice, whereinthe mobile terminal is served by a first core network node which isselected by the radio access network node based on the third informationindicating the first network slice, the at least one network slice beingindicated by a message including first information for the at least onenetwork slice, received from a second core network node which supportsthe at least one network slice.
 7. A communication system, comprising: aradio access network node; a mobile terminal; and a core network node,wherein the radio access network node is configured to: receive, fromthe core network node, a message for configuring with at least onenetwork slice supported by the core network node, wherein the messageincludes first information for the at least one network slice; andtransmit second information indicating availability of the at least onenetwork slice, the mobile terminal is configured to: receive the secondinformation; and transmit to the radio access network node, a RadioResource Control (RRC) setup complete message including thirdinformation indicating a first network slice from among the at least onenetwork slice, and the radio access network node is further configuredto: select a core network node specific for the first network slicebased on the third information indicating the first network slice.